Pit violinist Claudin hopelessly loves rising operatic soprano Christine Dubois (as do baritone Anatole and police inspector Raoul) and secretly aids her career. But Claudin loses both his touch and his job, murders a rascally music publisher in a fit of madness, and has his face etched with acid. Soon, mysterious crimes plague the Paris Opera House, blamed on a legendary "phantom" whom none can find in the mazes and catacombs. But both of Christine's lovers have plans to ferret him out.